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Topic Review (Newest First)

01-23-2013 06:00 AM

kso

Umm hmm, it's a good video. At a vantage point about 12-14" above the stock roll center, it illustrates the result of body roll and a little bushing squirm. If what you really want is for the tires to not move sideways in relation to the body, you could use a panhard rod or watts link to raise the roll center but then you're back to fighting the leaf springs again and it will get skittish over bad pavement on corners. A better solution for the car shown would be stiffer (or just new) spring bushings and more roll stiffness via swaybars or spring rate.

But anyhow, I think we're all tired of this one and I'm not going to get anywhere with it.

For the original poster, see some light-but-knowledgable discussion pro/con specific to the panhard bar issue here:

In the words of Forrest Gump... "that is all I have to say about that".

Thank you all for you input and insight.

Regards,

Andy

01-22-2013 02:24 PM

1971BB427

Same here. I understood, just didn't agree. That's what these discussions should be about, not about a contest to see how many will attack or flame.
I still think that the normal travel of a panhard bar is an arc, and as such it will try to push/deflect the springs sideways as the rear travels up and down. It's just not something I'd ever put on any of my vehicles.
If it's done because clearances are at a minimum, then those clearances must be enoughh that the arc of the panhard bar's travel wont push or pull the axle and create a further clearance issue.
By the way Andy, your build cars are amazing!

01-22-2013 01:17 PM

NEW INTERIORS

Only thing I was trying to point out here is.. By adding the panhard bar to fix one problem, Does it also create another one ???

Weighing out the real true benefits with a leaf spring set up..

I know Andy has some knowledge in chassis's,, But in the end is it worth the trouble to gain very little...

01-22-2013 12:10 PM

MARTINSR

Quote:

Originally Posted by kso

Well, we're telling a guy to put a panhard bar on his 1st-gen Firebird, which 95% would not do (my Guldstrand-built Camaro road-racer doesn't have one) and saying that leaf springs don't twist, which is dead-flat wrong.

So...what is it about? This is helping?

Later.

We were discussing it, my contribution was little more why I put one on my truck, and it wasn't for any other reason than to limit sideways movement of the rear so the tires wouldn't hit anything. We need to lighten up, I made a joke, that's all.

Brian

01-22-2013 11:59 AM

kso

Quote:

Originally Posted by MARTINSR

I am thinking that "someones" deflection angle is binding.

Brian

Well, we're telling a guy to put a panhard bar on his 1st-gen Firebird, which 95% would not do (my Guldstrand-built Camaro road-racer doesn't have one) and saying that leaf springs don't twist, which is dead-flat wrong.

So...what is it about? This is helping?

Later.

01-22-2013 11:44 AM

MARTINSR

Quote:

Originally Posted by aosborn

Look at the cars in my photo album and my avatar. Those are not theoretical, and they did not build themselves. There are plenty more where they came from.

What I am trying to do on these forums is to present a very complex subject in a way that is informative but not too heavy. If that is all you got out of my comments regarding leaf spring bushings and suspension binding, then you missed the point completely. If that is because I didn't explain it well, then my bad, if it is because you just didn't understand it, well...I tried.

Have a good day.

Andy

Andy, you have explained things well enough for my brain to get a grasp. I am thinking that "someones" deflection angle is binding.

Brian

01-22-2013 11:15 AM

aosborn

Look at the cars in my photo album and my avatar. Those are not theoretical, and they did not build themselves. There are plenty more where they came from.

What I am trying to do on these forums is to present a very complex subject in a way that is informative but not too heavy. If that is all you got out of my comments regarding leaf spring bushings and suspension binding, then you missed the point completely. If that is because I didn't explain it well, then my bad, if it is because you just didn't understand it, well...I tried.

Have a good day.

Andy

01-22-2013 10:47 AM

kso

Quote:

Originally Posted by aosborn

... If you did all aluminum bushings in both the front eye and the shackle, I would bet that you could hang the rear end nearly level with no support on the opposite side. I might try that the next time I have the opportunity. ...

I think you should try that, yes...you might be surprised. More easily (and accurately to negate the effects of any frame or bracket flexing), you could just clamp any old leaf-spring set in a vice with a means to measure deflection angle and then apply a torque wrench to the end.

I see a lot of book-reading here but not so much book understanding, and the meaning of "bind" is pretty-much lost in the wind along with where arc does and does-not mean anything. Said as a guy who canyon-raced for years and has built both coil- and leaf-spring cars. Just how much difference there is dialing in roll stiffness using sway bars on the different suspension types would be enough to let someone suspect what's going on when leafs are working...then if you take some actual measurements you might have actual knowledge. "Just saying".

Anyhow, you got the "roll-understeer" thing, which is something that most people don't have a concept of.

01-20-2013 08:08 PM

aosborn

Quote:

Originally Posted by 1971BB427

Never got into Autocross, but it is fun to watch. I built my '71 Camaro to be street driven, but handle well, and it does whatever I want, and usually more. I find I chicken out before the car has handling issues.
We like to take a drive in the summer up the windy Columbia River Gorge scenic highway, and push through the 10-20 mph curves as hard as our pucker factor will allow.

That is a great road, I have driven it many times myself. The next time you are out that way check out the road above the Maryhill Museum. SOVREN, the vintage road race guys, stage a hill climb there once a year. The road they run it on is the first paved road in Washington state and it is as curvy as a snake with a hunchback! I hope to run my Jeep on it sometime...

My test for cars was an exit off the freeway in my town that I took to go home. This exit is now gone, changed to new version of freeway exits (isn't that amazing how they are changing them all?).
Anyway this was one of those tight hairpin like corners that goes off to the right , up the hill of the overpass then back over the top of the overpass.

I use to take that exit off the freeway at 50+ keeping it at 50 all the way to the top of the corner at the overpass. That sucker really handles pretty good. Blown away a lot of high end sporty types I'll tell you that, hit a corner with them on your bumper and when you come out they are way back there, then with the good old Nailhead to the floor, you are gone. Fun stuff, it sort of replaced the stop light drag races I had as a kid all the time which of course are now long gone and I don't want them back actually. That was stupid as crap. But to hit a corner out somewhere that no one is at and all you hurt is you? What the heck, it's a good ride. And yes, I have hurt me. In that Gran Sport hitting a freeway entrance too hard, I apexed the corner hitting it hard and was over my head and blew over the curb with my new Goodyears and Roadwheels, bent the left front wheel all to heck, along with the tie rod end. As I was sliding sideways across the dirt I pushed the right rear tire right off the rim. I changed the tire on the side of the freeway and still made my date. Yep, a lot better than draggin down the street safety for others concerned.

I dig the autocross at the Goodguys events but it is a little slow for me, just a little faster would be a lot more entertaining but it still is damn fun to watch. I don't plan on getting out there, those guys are way too serious for me I wouldn't stand a chance.

Brian

01-20-2013 05:53 PM

1971BB427

Never got into Autocross, but it is fun to watch. I built my '71 Camaro to be street driven, but handle well, and it does whatever I want, and usually more. I find I chicken out before the car has handling issues.
We like to take a drive in the summer up the windy Columbia River Gorge scenic highway, and push through the 10-20 mph curves as hard as our pucker factor will allow.

01-19-2013 09:26 PM

NEW INTERIORS

Quote:

Originally Posted by aosborn

There are race cars, and there are street cars. If you want some of the benefits of a race car (better handling, more power etc) you couldn't do it without looking to the racing world for answers. You just need to tone it down a bit for the technology to work on the street. You should know all about this NEW INTERIORS. Take for example the Pro-Street cars you like to build. It is all race car technology toned down for the street.

I'm sure your cars go well in a straight line and do fine around town. As fast as you seem to like to go in a straight line, I like to go that fast in around corners. I drag raced for years and then I went to road racing school. Then I traded my 11 second 57 Chevy for a 455cid, 4 speed 76 Trans-am and have never looked back. Instead of having fun 11 seconds at a time a few times an afternoon, you can have fun for hours! But as you like to say "that's just me".

To each his own, that is what makes the world an interesting place.

When I was younger,, I grew up running some hard corners in my 73 Camaro.. Very bad road with a lot of cornering... Fun to run but at that time I was young and dumb.. I do hear where your coming from and do know you know... I just didn't see where it would make that much difference.... I know my 73 would handle very nice in some very tight cornering... The 69's much be way different then the 73's was.. I didn't see where it needed to be done on mine anyway...

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